As a waterproof structure for a conductive path, for example, a waterproof structure disclosed in the following Patent Document 1 is known. In FIG. 3, from a conductive path drawing part 52 of a connector housing 51, an electric wire 53 is drawn out. A seal member 54 is provided on the electric wire 53. This seal member 54 is provided to be watertight with respect to an inner circumferential surface of the conductive path drawing part 52. Also, the seal member 54 is provided to be watertight with respect to an outer circumferential surface of a cover of the electric wire 53. The seal member 54 is molded with an elastomer. A plurality of protrusions 55 is formed on an inner circumferential surface of the seal member 54.
The watertight state of the inner circumferential surface of the conductive path drawing part 52 and an outer circumferential surface of the seal member 54 is made by melting the elastomer with heat generated when the connector housing 51 is molded with a resin. Also, the watertight state of the inner circumferential surface of the seal member 54 and an outer circumferential surface of an insulator of the electric wire 53 is made by wedging the protrusions 55 into the outer circumferential surface of the insulator with pressure of the resin generated when the connector housing 51 is molded with the resin.